Rich rotifer assemblage (Rotifera: Eurotatoria) of a sub-tropical wetland of Meghalaya, northeast India: ecosystem diversity and interesting features

A total of 90 species, belonging to 29 genera and 15 families, observed from an urban wetland of Meghalaya is the species-rich Rotifera assemblage known till date from any sub-tropical ecosystem of the Indian sub-region. Total richness (S) merits biodiversity value as ~56.0, ~ 38.0 and ~23.0 % of the species recorded from Meghalaya, northeast India (NEI) and India, respectively while several rotifers of global and regional importance impart biogeographic interest. One species is new to NEI and 19 species (including two unidentified) are new to Meghalaya; this study resulted in an earlier report of five and two new records from India and NEI, respectively. The diverse Lecanidae > Lepadellidae together comprising ~ 57.0 % of S; largely littoral periphytonic nature of taxa; and distinct paucity of the Brachionidae and lack of Brachionus are notable features. The speciose Lecane, high richness of cosmopolitans and occurrence of several tropicopolitan and pantropical species impart broadly ‘tropical’ character to the fauna. With low monthly richness and low community similarities, our results affirm heterogeneity of rotifer species composition; the richness is positively influenced only by water temperature.